Question

Entrapped air normally exists in the form of relatively __________ air voids.

(a) Small

(b) Absent

(c) Large

(d) Medium

This question was posed to me in an internship interview.

This key question is from Water Proofing Admixtures in section Admixtures and Construction Chemicals of Concrete Technology

Answer 1

Correct choice is (c) Large

To explain: Entrapped air normally exists in the form of relatively large air voids, which are not dispersed uniformly throughout the mix, entrained air exists in the form of minute disconnected bubbles well distributed throughout the mix.